BBC Marconi AXBT Microphone & matching desk stand

BBC Marconi AXBT microphone Type A, manufactured by Marconi, c. 1944. BBC ribbon microphone with stand.

In the early 1930s, the gold-standard microphone for radio broadcast was the RCA 44A, made in the US, but these were too expensive for the BBC to buy and import in the numbers needed for their rapidly growing broadcast output. They worked together with the Marconi Wireless Company to develop a similar microphone at a much more affordable cost, which resulted in the AX model in 1934, which was a tenth of the cost of the RCA. With only minor modification, such as this AXBT model from around 1944, these microphones remained in production until 1959, and were used at the BBC into the 1960s.

The ribbon microphone contains an aluminium ribbon, less than a thousandth of a millimetre thick, which vibrates in response to the tiny pressure changes caused by a sound wave. This movement of the ribbon between the poles of a large magnet generates an electrical current which reflects the shape of the the sound wave.